The central premise of this proposal is that effective biomedical sensors must interface with biological systems at the molecular scale. These devices must extract and process information from a complex environment of interacting non-linear biomolecular processes and, in an ideal embodiment, intervene in processes gone awry. Functionality at this level of complexity dictates the requirements of engineering functional nanoscale components within microscale structures, facilitating highly complex processing schemes that can be implemented in very small volumes. Nature's answer to this design challenge is the cell. The objective of this work is to develop sensors that mimic the dimensions and some portion of the functionality of a cell. By mimicking cellular features, effective operation and interfacing to biological systems be achieved. To realize this ideal, we will exploit advances in nanofabrication that allow for the synthesis of physical features on length scales ranging from nanometers to centimeters. Carbon nanofiber- based membranes, will be arranged to create small volume containers. The nanoscale features of these membranes will be engineered to control chemically specific transport that influences enzyme-based reaction systems assembled within these containers. The resulting cell mimic structures will allow for physically and chemically specific sensing and for implementation of complex, engineered biochemical networks in contained volumes and under concentration conditions that closely model those of natural cells.